Process for distilling and cracking oils



Patented Apr. 15, 1924.

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' To all whomc't may concern:

Be it known that I, Venom T. SMITH, a citizen of the United States. and a resident of San F rancisco,'county of San Francisco, State of California, have invented a new and useful Process for Distilling and Cracking Oils, of which the following is a speciw p in the first unit are cracked whi e in the fication.

' The present invention relates toimprovements in process for distilling and cracking of hydrocarbon oils, especially of such of a heavy grade. The proposed process is of the, two-unit type in one of which units the oil to be cracked is distilled while in the second unit the oil vapors roduced vapor phase.

The apparatusfor the proposed process consists essentially of two retort units of the gas producer type one of which is a distilin retort and the other a cracking retort. eat for accomplishing the proposed reactions of distillation and crackmg is furnished by the combustion of solid carbonaceous fuel, preferably coke, within the two retorts. 'DlStlllfltlOD and crackin of oil is obtained by direct contact witi heated fuel and gases; proper temperature of fuel being maintained and automatically regulated by continuous combustion of fuel in definite areas of retorts. The retort units with attached heat interchangers and condensers etc. operate as a single system continuously and withexceptions as to details of equipment are the basis of the process upon which novelty is claimed.

The preferred form of the invention is illustrated in the accompanying drawing which shows an arrangement of apparatus, mostly in vertical section, by means of which my process may be executed. While I have shown only the referred form of my invention it should be understood that various changes or modifications may be made within the scope of the claims hereto attached without departing from the spirit of the invention.

(1) is the primary distilling retort. For simplicit it ma be considered as a simple gas pro ucer. n operation the retort is charged with fuel from the char 'ng hop er (2) to aroper level in t e retort. he fuel bed 0 colre is then kindled at the grates (3) the air fer combustion entering under pressure at the nozzle (4) beneath. the

grates. Upon the top of the fuel bed' reach-' mg the dlstillin temperature of the oil to be cracked, t e oil which is reheated m the coil (6) 'is pumped or breed in upon the topof the fuel bed, the vapors distillin off by contact with the hot fuel. any co or asphaltic residue from the 011 is deposited upon the fuel, being itself burned as fuel as it drops through the retort.

.Combustion of the oil is prevented by the non-oxidizing atmosphere maintained at all times in the distilling zone by the presence of waste gases from thecombustion zones. The oil is fractionally distilled partly by surface evaporation as it flows over the heated fuel by gravity. There is a constantly increasing temperature from the top to the bottom of the retort and the various fractions of the oil are distilled 011' as they reach their zone of distilling temperature. The height of the fuel bed is maintained by the addition of fuel from the charging hopper (2)., any excess formed 'by deposition of carbon from the oil being drawn from the discharge chamber (7) adapted to be closed.- by the.

gate (9). Means are provided for breaking up the fuelbed due to excessive deposition of asphaltlc material in the top of retort by the hand-operated agitator (8). Proper v v provision is also made for admitting air under any desired pressure by the air pump (11) and by other means described hereinafter and also for withdrawing ashes or clinker through the bottom of the retort, as shown at (12).

The oil vapors and combustion gases pass from the distilling retort (1) through a heat interchanger (13) into the secondary or cracking retort (14) which is a modified gas producer. In construction it is a horizontal chamber (16) with multiple combustion chambers (17). The coke fuel. com letegy fills the retort and is maintained full y a dition from a charging hopper (18) in the top of the retort. The coke in the horizon-- tal chamber acts as an absorbing medium for the heat generated in the combustion chambars in the base of the retort and in operation is automatically maintained at the the thermostat (33). The thermostat rod containing an enclosed gas chamber (31) extends into the body of coke, the gas chamber lying in the path of the oil vapors.

A hollow metal tube communicates from the gas chamber (31) to the flexible diaphragm (34) in the thermostat (33). The pressure generated by expansion of the gas m chamber (31) due to increase in temperature of the surrounding coke is transmitted to the locationof chamber (31). The oil vapors issuing 'from the primary distilling retort are passed through this horizontal coke bed Y and cracked, the free carbon resulting from the decomposition of the oil separating out and depositing upon the coke fuel which in turn is burned upon it reaching the combustion areas in the base of the retort. Means are provided for admitting fuel to the retort chamber. The cracked vapors from the secondary retort pass through the heat mterchanger (13) preheating t e vapors from the primary retort. From the interchanger the vapors and gases pass through a waste heat steam boiler (19) maintained at constant temperature by constant pressure for fractional condensation of oil vapors and for generation of steam used in blasting the' grates during'combustion of fuel to reduce excessive temperature and prevent formatlon of clinker from the ash in the fuel. The heavy distillates resulting from this process are collected in the tank (20) and the steam nerated is distributed through the pipes 20) From the waste heat boiler the gases pass through a cooler (21), which condenses portions of the oil vapors not condensed in the waste heat boiler. From the cooler the fixed gases still under pressure pass through a second cooler e(22) and thereafter the pressure is utiliz to drive an engine (23) which is coupled to a com ression pum (24)furnishing the principa suppl of air required for the combustion of t 0 fuel. The expansion of the gasin the engine redrop in' temperature of the sults in a great gasesiwhic is utilized in the refrigeration of the expanded as in the cooler 22) for removal of any lig t oil vapors by condense tion. Means are 'rovided in the pi (26 for returning the envy uncracked dlsti late condensed in the waste heat boiler to the distilling retort for further cycling through the apparatus The light cracked distillate condensed in the condenser is drawn off from the receiving tank (27) and mixed with the light naphtha from the receiving tank (28) for sures on account of the lower gas-losses resulting from the cracking of the oil and the higher quality of the cracked products.

The advantages of the proposed process lie in its extremely high fuel economy on account of direct application of heat for distillation and cracking: and also the ability of the process to handle very heavy oils of high asphaltic or carbon content. Deposition of carbon from the cracking isupon the fuel itself and not upon the walls as in the case of externally heated retorts where formation and accumulation of carbon cause nus-functioning and failure of apparatus. In fact, the deposition of carbon from the 011 in my process is sin-advantage, inasmuch as it furnishes fuel for the required operation and is in such shape that it can be utilized to greatest advantage at its point of formation.

The principal feature of the present invention lies in the application of direct heat 1 for cracking and distilling .the oil, heat being obtained by the internal combustion of solid fuel inside the retort which acts as a receiver of carbon formed by cracking as well as a distributor for the oil and vapors and contact surface requisite to the cracking reaction.

Thecracking operation is preferably carried out at temperatures of 900-1300 Fahr.

I claim:

1. The process of distilling and cracking oil which consists in engaging the oil with a bed of combustible carbonaceous material increasing in temperature in the direction of the flow of oil whereby the oil is vaporized and in guiding .the vapors so produced through a bed of combustible carbonaceous material maintaining -constant tem erature in the direction and path of flow o the vapors for cracking the same.

2. The process of distilling and crackin oil which consists in engaging the oil with a bed ofv combustible carbonaceous material heated by burning same at the bottom and increasing in tem rature in the direction of the flow of oil wliiireby the oil is vaporized and in guiding the vapors so produced throu h a bed of combustible carbonaceous material heated by burning same at the bottom and maintainin a constant tem rature in the direction an path of flow orthe vae pors for cracking the same.

The processof distilling and cracking o1 scend into a bed of combustible carbonaceous Ill which consists in causing the oil to dc v material heated by burning the same at the bottom and increasing in temperature toward the bottom whereby the oil is vaporized and in guiding the va rs soproduced laterally through 'a, bed 0 combustible carbonaceous material heated b'yburning the same at the bottom andmaintaining a constant temperature in the direction and path of flow of the vapors for'cracking the same.

4. The process of distilling and cracking oil which consists in causin the oil to descend into a bed of combustib e'carbonaceous material increasing in temperature toward the bottom whereby the oil is vaporized and in guiding the vapors so produced laterally through a bed of combustible carbonaceous material maintaining a constant temperature in the direction and path of flow of the vapors for crackingthe same.

5. The process of cracking oil vapors which consists in guiding the same through a' body of combustlble carbonaceous material heated by burning the same at the bottom and maintaining a' constant temperature inthe direction and path of flow of the vapors. 6. The process of cracking oil vapors whichconsists in uidirig the same laterally through a body of combustible carbonaceous material and in heating the latter by burn-- ing the same at' the bottom in the presence of a controlled supply of compressed air. 7. The process of distilling and crackin oil which consists in engaging the oil wit a bed of combustible carbonaceous material increasing in temperature in the direction of flow of oil whereby'the oil isivaporized, in guiding the vapors so produced through a bed of combustible carbonaceous materlal maintaining a constant temperature in the direction and path of flow of the vapors for cracking the same, and in guiding the cracked vapors ast the uncracked vapors for preheating t e latter.

' VERGIL T. SMITH. 

